Chemistry Lab Handout 11   "Covalent, Ionic & Hydrated Crystals"

Your Name:    ___________________________________ Role:______________

Lab Partners: ________________Role:_____   ________________Role:_____

Problem:  How can heating substances help determine the type of bonding      in a crystal?

Hypothesis:   _______________________________________________________

     _________________________________________________________________

     _________________________________________________________________

Materials:                   2 small test tubes   bunsen burner
     burner striker          test tube clamp      test tube rack
     scoopula                Sodium Chloride      Sugar
     Copper(II) Sulfate Pentahydrate              water
     dropper                 clock                goggles

Caution: 

Procedure:
1. Obtain goggles and wear them for the entire lab!
2. Place a small scoop of Sodium Chloride crystals in a small test
     tube.
3. Turn on the burner gas and light the burner with a striker.
4. Using a test tube clamp hold the test tube in the blue part of the      flame with the mouth of the test tube toward the wall.
5. Observe the crystals every minute for a total of four minutes.  Record your observations in the table below.
6. When finished place the test tube on a piece of Aluminum foil in the      test tube rack to cool and turn off the bunsen burner.
7. Place a small scoop of Sugar crystals in the second small test tube.
8. Repeat steps 3-6 then go to step 9.
9. Empty the Sodium Chloride crystals from the first test tube after      they have cooled to room temperature.
10.Place a few Copper(II) Sulfate Pentahydrate crystals in the first      small test tube.
11.Repeat steps 3-6 then go to step 12.
12.After a few minutes of cooling, add a few drops of water to the      Copper(II) Sulfate Pentahydrate crystals and record your observations.

Observations:
     Description of Sodium Chloride crystals:

          Before heating:

          After 1 minute:

          After 2 minutes:

          After 3 minutes:

          At end of heating:

Observations: (cont.)
     Description of Sugar crystals:

          Before heating:

          After 1 minute:

          After 2 minutes:

          After 3 minutes:

          At end of heating:

 

     Description of Copper(II) Sulfate Pentahydrate crystals:

          Before heating:

          After 1 minute:

          After 2 minutes:

          After 3 minutes:

          At end of heating:

          After step 12:

Data: (none)

Diagram:

 

 

 

 

 

 

Conclusion:   _______________________________________________________

     _________________________________________________________________

     _________________________________________________________________

Questions:

1. What type of bonding exists for each of the three crystals?
2. List one other example of a compound for each type of bonding.
3. What did the Copper(II) Sulfate Pentahydrate change into when
     heated?
4. What compound was formed when you added water to the crystals?

Answers: